1. Field of the Invention
The present invention relates to a method and apparatus for monitoring, i.e. supervising burdens, such as ore and coke, in a blast furnace, located in a high temperature-range portion therein. Here, the term "supervise" means specifically, to detect distribution of burdens, positions of the ore layers, coke layers, the mixture thereof and the layers of the cohesive ore, hereinafter called "cohesive layer", the descending velocity of the burdens and the cohesive layer, the particle size of the ore and coke, the thicknesses of the ore, coke layers and cohesive layers, and so on.
2. Description of the Prior Art
In improving the operation of blast furnaces, it is important to supervise the burdens, especially the burdens located in a high temperature-range portion, i.e., the belly and bosh of the blast furnace.
Several techniques for such supervision have been proposed in the prior art, but these techniques are applicable only to burdens located in a relatively low temperature-range portion, e.g., lower than 400.degree. C., in the furnace. For example, U.S. Pat. No. 4,122,392 proposes to supervise burdens by distinguishing the ore and coke from each other by the difference in magnetic characteristics. Another proposal is to distinguish the ore and coke from each other by detecting the difference in electric resistance.
There are problems, however, with these prior art methods. Magnetic characteristics cannot be measured at temperatures over the Curie point. Also, electrodes for measuring electric resistance deteriorate in conductivity due to the high temperature and as a result of sticking of dusty materials thereto. Thus, the prior art methods are effective only in the low temperature range. Accordingly, it is impossible to supervise the cohesive zone of cohesive layers at a bosh level, which is in a considerably high temperature range.